Motor vehicle door latch

ABSTRACT

A motor-vehicle door latch wherein a coupling body on the doorpost is lockingly engageably by a pawl on the door edge which, in turn, is blockable by an operating lever. The latch has an actuating member which is operated by the door handles and is connected by a link to the operating lever. The actuating member is formed with a slot in which a pin carried by the locking mechanism is engaged. The operating lever has a guide surface with which the pin is only engageable when the pin is towards one end of the guide slot. Thus when the pin is at the other end of the guide slot the two elements are effectively disconnected and the door cannot be opened by actuation of either of the handles. But should either handle be retained in the actuated position and the locking mechanism be operated to unlock the door, the link will move along in the groove, engage the guide surface on the operating lever, and cam this lever over to free the pawl and operate the lock. This pin is made of a synthetic resin having a low coefficient of friction such as polytetrafluorethylene.

United States Patent 1 Kleefeld et al.

{ 1 MOTOR VEHICLE DOOR LATCH [75] Inventors: Frank Kleefeld, Heiligenhaus;

Gunter Gmeiner, Sindelfingen, both of Germany [73] Assignees: Arn. Kiekert Sohne, Heiligenhaus;

Daimler-Benz Aktiengesellschaft, Stuttgart-Unterturkheim, both of, Germany 22 Filed: Mar. 19,1973

21 Appl. No: 342,804

[30] Foreign Application Priority Data Mar. 7, 1972 Germany 2213190 [52] US. CL... 292/216, 292/DIG. 26, 292/DIG. 38, 70/464 [51] Int. Cl. E05c 3/26 [58] Field of Search 292/216, 280, DIG. 38, 292/D1G. 26; 70/464 [56] References Cited UNITED STATES PATENTS 3,121,580 2/1964 DiSalvo et al. 292/D1G. 27 3,487,667 1/1970 Russell et a1 70/464 3,695,662 10/1972 Ploughman 292/D1G. 26 3,697,105 10/1972 Marx 292/D1G. 27

Lock

11 3,858,919 Jan. 7, 1975 Primary Exa minerRichard E. Moore Attorney, Agent, or Firm-Karl F. Ross; Herbert Dubno link to the operating lever. The actuating member is formed with a slot in which a pin carried by the locking mechanism is engaged. The operating lever has a guide surface with which the pin is only engageable when the pin is towards one end of the guide slot. Thus when the pin is at'the other end of the guide slot the two elements are effectively disconnected and the door cannot be opened by actuation of either of the handles. But should either handle be retained in the actuated position and the locking mechanism be operated to unlock the door, the link. will move along in the groove, engage the guide surface on the operating lever, and cam this lever over to free the pawl and operate the lock. This pin is made of a synthetic resin having a low coefficient of friction such as polytetrafluorethylene.

4 Claims, 4 Drawing Figures PATENTEDJAN mrs 3,858,919

sum 10! 5 PATENTEDJAH 7197s SHEET 2 OF 3 Luz FIG. 2

PATENTED JAN 7 5 SHEET 3 [IF 3 1 MOTOR VEHICLE DOOR LATCH FIELD OF THE INVENTION The present invention relates to a latch and, more particularly to a lockable motor-vehicle door latch.

BACKGROUND OF THE INVENTION In a conventional motor-vehicle door latch a coupling body on the doorpost is engageable with a locking pawl carried on the door edge. An operating lever or other similar element cooperating with such a lever is formed as a keeper and is engageable with the locking pawl to prevent its displacement unless the inner or outer door handle is operated. As a general rule an actuating lever or member isprovided which is directly coupled to the two door handles, and a link is provided between this member and the keeper lever. A locking mechanism can act on this link to decouple the keeper from the door handles so that the door is locked. The link is usually a bent-over tab projecting from one of the levers, and one of the levers has a pivot displaceable by the locking mechanism into a position wherein the tab does not grasp the other lever. This, of course, ensures that the handles will be ineffective until the movable lever is displaced back to its position in which the tab is effective.

With such locks, displacement of the actuating member with the locking mechanism in an actuated state brings the various elements out of line with each other so that, even if the locking mechanism is operated. to unlock the door, the handle must be released and then actuated again to open the door. This is often a bother when a person trying to open the door for another operates the outer handle before the person inside has unlocked the door. More important, in cases in which an accident has occurred is it often the situation that the inner or outer door handle is jammed in the actuated position (pressed in or drawn out) so that, with the door locked, it is impossible to open the door. For instance should something become wedged under the outer door handle while the door is locked, the passenger cannot unlock the door from the inside since even if the locking mechanism is operated, the outer handle has to be returned to its unactuated position before the various elements of the mechanism allow the handles to function to open the door. A similar problem faces the rescuer.

OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide an improved door latch of economical construction and reliable operation effectual to permit in a vehicle lock construction of the character described, convenient escape of a passenger should an accident befall the vehicle.

Another object is the provision of a motor-vehicle door latch which overcomes the aforementioned disadvantages.

SUMMARY OF THE INVENTION These objects are attained according to the present invention in a latch wherein the actuating member (that element which is operated directly by the door handles and can even be a guide on the operating lever, which is that element that blocks or unblocks the locking pawl. The link ,is displaceable along one of the guides between two locations, in the first of which it couples the actuating member to the operating lever, and in the second of which it permits displacement of the actuating member without displacement of the operating lever. This second position corresponds to the locked position of the door. Locking mechanism is provided for displacing this link back to the first-described position when the actuating member is in the actuated position so as to engage this link against the other guide and cam the operating leverover and free the pawl. Thus if one of the door handles is for some reason retained in the actuated position with the locking mechanism in the locked position, simple operation of the locking mechanism will unlock and open the door.

According to another feature of this invention the locking mechanism is formed of a chain of levers pivoted on the latch housing, one of the levers having an arm carrying a pin which constitutes the link.

More specifically, the link is made of a synthetic resin having a low coefficient of friction polytetraflourethylene (Teflon) being found advantageous, and rides in a groove or slot on the actuating member and is engageable with a guide surface on the operating lever.

DESCRIPTION or THE DRAWING The above and other objects, features and advantages will become apparent from thefollowing with reference tothe accompanying drawing in which:

FIG. 1 is a perspective view of the latch according'to the present invention;

FIG. 2 is a perspective view of the latch seen in the direction of arrow II of FIG. 1; and

FIGS. 3 and 4 are diagrammatic views illustrating operation of the latch in the unlocked and locked positions, respectively.

SPECIFIC DESCRIPTION As shown in FIGS. 1 and 2 the latch comprises an L- shaped housing 2 adapted to be mounted at the edge of a motor vehicle door with its longer side 2' extending tangentially of the doors pivot axis and its shorter side 2" lying in a plane parallel to the plane of the door. A coupling element 3 is engageable in a cutout 4 formed in the housing 2. This heavy steel element 3 is secured to the vehicle doorpost. A second steel plate 36 is riveted to the inside of housing 2 to close the inside of cutout 4.

Provided within the cutout 4 is an outwardly directed pin 19 having a frustoconical end 19' receivable within a correspondingly shaped socket or hole 20 in the coupling element 3 which is formed with a pair of ledges 21 which engage under the edges of cutout 4 to secure the element 3 tightly within the housing 2 and insure an exact positioning of the door relative to the doorpost in the closed position of the door.

The element 3 is provided between its ledge 21 and main body with two parallel steel pins 5 which coact with teeth 22 of a locking pawl 1 pivoted at 23 on the housing side 2' and the plate 36 below the cutout 4. The pawl l is shown in FIG. 1 in solid lines in the position it assumes with the door closed and in dot-dash lines in the door-open position. The pins 5 act as the teeth of a rack which mesh with the teeth 22 of the pawl 1.

This pawl l, as shown in FIG. 2, is normally biased by a spring 24 into the dot-dash line position of FIG. 1, but can be stepped in either the solid-line position of FIG. 1 or an angular position intermediate the two by engagement of an element 6 with either of two teeth 25 formed on the pawl. The element 6 is a two-arm lever pivote'd at 7 on the side 2 and having an arm 9 by which it is operated and an arm 26 having an end 27 acting as a keeper and engageable with the teeth 25 to block the pawl l. A spring 28 is provided to urge the end 27 against the pawl l.

The door is opened by actuation of an inside or outside door handle 29. which pivots a lever 8 about its axis 30 on the side 2 in the direction shown by arrow 14. This is shown in FIG. 3 where a coupling bolt of polytetrafluorethylene is shown engaged in a slot 16 formed in the lever 8. Displacement of the lever in direction l4 pushes the bolt 15 against the actuating arm 9 of the operating element 6 to pivot this element back and free the pawl. In FIG. 3 the actuated position is shown in solid lines and the unactuated position in dotdash lines.

A locking lever 11 is pivoted at 10 on the side 2" of the housing 2. When a'locking button 31 on the vehicle door is depressed or when a lock cylinder 32 is rotated this element 11 pivots a lever 12 pivoted on the housing 2 on a pin 37 at the base of the cutout 4 in the direction .by arrows 13. Another element 33 is pivoted on this lever 12 and engageable with the pawl l to prevent the vehicle door from being shut'with the button 31 depressed so as to makeit impossible for the operator to lock his keys in the car. Pivotal on a pin 34 on the end of lever 12 is an operating arm 35 on whose end the Teflon pin 15 is mounted.

When the button 31 is depressed or the lock cylinder 32 rotated with the door closed the lever, 11 will pivot to slide the pin 15 down in the slot 16 toward the axis 30. FIG. 3 makes it clear that if the pin 15 is in this position pivoting of the lever 8 from the dot-dash position to the solid-line position will not operate the arm 9 of lever 6 since the pin 15 will not couple the two together. The pin 15 will not engage this arm 9 at all.

Should for some reason the door handle outside the car be actuated or the handle inside the car be similarly actuated with the door locked so that a person on the other side of the door is unable to open the door from his side, all that person need do is operate his unlocking mechanism 31 or 32. This unlocking will pivot the lever 12 to slide the pin 15 up in the slot 16. As shown in FIG. 4, when the unlocking lever 8 is in theactuated, solid-line position and the pin 15 is down in the locked position, operation of the locking mechanism will slide this pin 15 up in the direction of arrow 18 along the curved inside surface 17 of the operating arm 9 to force the lever 6 back and free the pawl 1. Thus in an accident or the like the door can be opened, even though locked, from the inside or outside even though the handle on the other side is for some reason blocked in the actuated position.

We claim:

1. A door latch comprising;

a coupling body adapted to be mounted on a motorvehicle doorpost;

a housing adapted to be mounted on a motor-vehicle door;

a locking pawl displaceable on said housing and lockingly engageable'with said body;

an operating lever on said housing having a keeper engageable with said pawl and displaceable between an actuated position permitting displacement of said pawl thereby freeing said door from said doorpost and an unactuated position blocking displacement of said pawl thereby securing said door to said doorpost, said lever being formed with a guide surface;

anactuating member pivotal on said housing and formed with a guide slot, said pawl, said layer, and said member being pivotal on said housing about generally parallel axes;

a locking arm displaceable on said housing transverse I to said axes;

a link pin fixedly mounted on said arm and displaceable along said slot between a first location therein engageable with said surface and a second location therein wherein engagement with said surface is impossible said pin being displaceable toward and away from said guide surface;

means for displacing said member. from a first to a second position with said link pin at said first location engaging said guide surface of said lever and displacing said operating lever into said actuated position and with said link pin at said second location for leaving said lever in said unactuated position; and

locking means connected to said arm for displacing said link pin in either position of said member from said first to said second location for decoupling said member from said lever and for displacing said link pin against said guide surface and forcing said operating lever from its unactuated position to its actuated position.

I 2. The latch defined in claim 1 wherein said locking means includes mechanism having a pivot on said housing for displacing said arm.

3. The latch defined in-claim 2 wherein said actuating member is a lever having a pivot on said housing independent of said pivot of said mechanism.

4. The latch defined in claim 1 wherein said pin has a low-friction surface composed of polytetrafluorethylene. 

1. A door latch comprising; a coupling body adapted to be mounted on a motor-vehicle doorpost; a housing adapted to be mounted on a motor-vehicle door; a locking pawl displaceable on said housing and lockingly engageable with said body; an operating lever on said housing having a keeper engageable with said pawl and displaceable between an actuated position permitting displacement of said pawl thereby freeing said door from said doorpost and an unactuated position blocking displacement of said pawl thereby securing said door to said doorpost, said lever being formed with a guide surface; an actuating member pivotal on said housing and formed with a guide slot, said pawl, said layer, and said member being pivotal on said housing about generally parallel axes; a locking arm displaceable on said housing transverse to said axes; a link pin fixedly mounted oN said arm and displaceable along said slot between a first location therein engageable with said surface and a second location therein wherein engagement with said surface is impossible said pin being displaceable toward and away from said guide surface; means for displacing said member from a first to a second position with said link pin at said first location engaging said guide surface of said lever and displacing said operating lever into said actuated position and with said link pin at said second location for leaving said lever in said unactuated position; and locking means connected to said arm for displacing said link pin in either position of said member from said first to said second location for decoupling said member from said lever and for displacing said link pin against said guide surface and forcing said operating lever from its unactuated position to its actuated position.
 2. The latch defined in claim 1 wherein said locking means includes mechanism having a pivot on said housing for displacing said arm.
 3. The latch defined in claim 2 wherein said actuating member is a lever having a pivot on said housing independent of said pivot of said mechanism.
 4. The latch defined in claim 1 wherein said pin has a low-friction surface composed of polytetrafluorethylene. 